Castles in the cliffs: Archaeology and myth in the Pyrenees.

The spa town of Ornolac-Ussat-les-Bains lies in the French Pyrenees 15km south of the county town of Foix. From the Rue des Thermes, or Bath Street, a path climbs diagonally across a steep hillside, forcing its way through prickly vegetation until the gradient becomes so severe and the drop from the path so sheer that some kind person has fitted metal posts and a wire handrail. At the foot of a towering limestone cliff, the first man made walls emerge from the undergrowth. The path turns sharply through the remnants of a stone gateway, passes a cave the size of a sentry box, and makes a double dogleg through the ruins of a barbican. From here, a few more paces lead on to a sandy area the size of a couple of tennis courts. Look up, and this unusual bailey is sheltered from rain and shine by the roof of a natural porch 20m high. This monumental porch ends at a buttress whose central part appears to have been faced with masonry, but in its centre an arched doorway leads to the innermost recess of this bizarre castle.

Through the threshold, seven wooden steps descend into a cavern shaped like a railway tunnel, large enough to house a locomotive, but too short to include the carriages. At its far end, a full-length window in the rock overlooks the Ariège valley. The road to Andorra and Spain is close enough for a watchman to identify friend from foe.

As is so often the case in this place, there is nothing military about the most recent signs of human activity. Candles have left trails of red wax on the rock walls and their stubs hide in nooks and crannies. A potted rose withers by the window. Near the wooden steps, a massive slab of rock lies flat on three round stones, resembling an altar. On its upper surface, red soil and marguerite daisies have been arranged to resemble the Occitan cross, or the cross of the Cathars.